THURSDAY, Oct. 8, 2026 (HealthDay News) -- Greater childhood and adolescent fitness is associated with a lower risk for adult depression, according to a study published in the December 1 issue of the Journal of Affective Disorders.Kylie J. Smith, Ph.D., from University of Tasmania in Australia, and colleagues examined associations between childhood and adolescent cardiorespiratory fitness (CRF) and muscular fitness and adult depression. The analysis included data from 1,062 Australian children and adolescents (ages 7 to 15 years) who were followed for a mean 32.5 years (ages 36 to 49 years).The researchers found that greater childhood and adolescent CRF (1.6 km run speed) was associated with a lower risk for adult depression (females: hazard ratio, 0.80; 95 percent confidence interval, 0.65 to 0.99; males: hazard ratio, 0.89; 95 percent confidence interval, 0.67 to 1.19). For muscular fitness, associations were weaker and nonsignificant."There are many contributing factors to depression, meaning no single factor explains risk on its own. Fitness may be one piece of the puzzle," Smith said in a statement. "While we cannot say a lack of fitness during childhood causes depression in adults, the findings suggest that childhood fitness may have benefits beyond physical health."Abstract/Full Text .Sign up for our weekly HealthDay newsletter